The present invention relates to materials having light weight and low cost, as well as superior low friction, energy absorption and dirt management characteristics, for use in automotive and equipment applications where parts move relative to each other. In particular, the present invention relates to a molded, bristled material which is particularly suited for use as a glass retainer in a channel, track or race in which glass is slidably disposed.
Of the numerous mechanical, moving parts in automobiles, sliding windows have long been the subject of improved operation. Typical concerns have focused on window movement with minimum effort; window tracking; sealing against the environment; energy absorption to protect the window during opening and closing, and to prevent rattles and squeaks; and grit management to prevent window scratching. These concerns have been addressed by various window channel designs.
Window channels in automobiles are known which incorporate resilient filaments which receive and seal at least part of a sliding window in a window opening. For example, Brueder, U.S. Pat. No. 2,878,056, issued Mar. 17, 1959, discloses a sliding window glass arrangement in which a brush-like member having filaments extending from a compressible mounting, extends across the bottom edge or belt of the window opening to engage the inner window surface.
More recently, automobile window openings for sliding windows, representatively shown in FIG. 1, have been provided with flocked, C- or J-shaped channels 10b disposed in metal supports 12, as shown in FIG. 2. This "sealing lip" design has been widely used, and is lightweight and inexpensive. The flocked surfaces provide good wear sealing, energy absorption, and grit management characteristics Flocking is well known in the art and comprises the addition of small fibers 14, such as polypropylene fibers, to the surface of a carrier, such as cloth, rubber or plastic. Flocking reduces the surface contact and, thus, the friction, between a moving window 16 and a channel 10 in which it moves.
Such flocked channels have been used in both the window openings and hidden window races 22a, 22b in automobile doors 20, shown in FIG. 1. Typically, the forward channel 10a is continuous with the forward window race 22a to maintain window alignment, while the rearward channel 10b is discontinuous with rearward window race 22b, to allow removal of the latter to facilitate window replacement and adjustment.
Although widely used, flocked channels 10 have, nonetheless, had some drawbacks in operation. Over time, the flocking fibers 14 wear off through contact with the window surfaces. Increased efforts are required to overcome the more intimate frictional contact with the carrier material, and window motor burnout occurs more easily. As well, the continuous contact between the window 16 and the channels 10a, 10b and races 22a, 22b causes the leading edge of the window 16 to propagate waves in the channels 10a, 10b (when moving upward) and races 22a, 22b (when moving downward) which add resistance to the window motion. The increased force required for window operation further contributes to window motor burnout. As well, the channel deformation which characterizes the resistant wave contributes to breaking down and wearing off the flocking, with the consequent effect on window motor burnout discussed above.
Accordingly, the need remains for further development of low-cost materials and designs which reduce the resistance to window motion, and which also exhibit energy absorption and dirt management characteristics. More generally, the need remains for continued development of materials and designs for automotive and equipment applications to reduce friction, wear and related problems arising from contact between moving parts.